SEOUL, Dec. 6 (Yonhap) -- North Korea has increased the number of public executions in a bid to suppress internal dissent in the communist regime, a South Korean lawmaker said Friday, citing intelligence from the state spy agency.

The growth in public executions comes as Pyongyang has tried to strengthen its "reign of terror" over the North Korean people, Rep. Cho Won-jin of the ruling Saenuri Party said in a press briefing following a meeting of the parliamentary intelligence committee.

Last year, North Korea executed 17 people in public, with the number growing to more than 40 this year, he said, citing National Intelligence Service (NIS) chief Nam Jae-joon at the meeting.

"These executions are aimed at setting an example and quelling complaints from within," Cho said.

The revelation follows an earlier report by the spy agency that Jang Song-thaek, the powerful uncle and guardian of North Korean leader Kim Jong-un, appears to have been removed from all his posts.

Nam told lawmakers again that there is a lot of evidence pointing toward Jang's dismissal.

The report sparked speculation that a major power shift is under way within the communist regime.

Two of Jang's confidants were reported to have been publicly executed in connection with the uncle's purge.

The NIS chief confirmed that a brother-in-law and nephew of Jang had been forcefully summoned back to the North, Rep. Jung Chung-rai of the main opposition Democratic Party said in the joint press briefing.

However, Nam denied any knowledge of reports that one of Jang's closest aides had sought asylum in China, according to Jung.

The intelligence chief also told lawmakers that while Kim's grip on power seemed tight, recent developments may contribute to instability in the communist regime. He speculated that with the uncle out of the picture, the influence of Choe Ryong-hae, the director of the military General Political Bureau, may grow in the future.

He said that because no physical harm seems to have befallen Jang, there is a chance he may make an appearance at the memorial service for late leader Kim Jong-il, who is the father of the current leader.

The NIS, meanwhile, said the North has amassed a large number of high-caliber multiple rocket launcher systems near the de facto inter-Korean sea border, called the northern limit line, in the Yellow Sea off the west coast.

It said about 60 attack helicopters have also been observed in the area, which can pose security threats to the five South Korean islands near the border.

The so-called Seohae islands, including Baengnyeong, Daecheong and Yeonpyeong, witnessed several bloody clashes. The North Koreans sank a South Korean warship in March 2010 and shelled Yeonpyeong Island eight months later. The two incidents took the lives of a total of 50 South Koreans and raised tensions on the Korean Peninsula.